GUS

DIGITAL SEISMIC DATA RE-RECORDING SYSTEMS AND COMPONENTS THEREOF COMPRISING ESSENTIALLY, LEAKAGE AND CONTINUITY TESTERS, LINE BALANCE CONTROLS AND TESTERS, MULTICHANNEL SWITCH UNITS, DIGITAL SEISMIC AMPLIFIERS, CIRCUIT NOISE TESTERS, BINARY GAIN AMPLIFIER UNITS, DIGITAL-TO-ANALOG CONVERTERS, ANALOG-TO-DIGITAL CONVERTERS, COMPUTERS INTERFACES, MULTIPLEXERS AND DEMULTIPLEXERS, FILTERS, AND AIRCRAFT RATE OF CLIMB INDICATORS